Material handling equipment

ABSTRACT

An attachment for a lifting vehicle, particularly a fork lift truck, comprising a rear frame having means for attachment to a vehicle; a mid-frame; a first hinge between the rear frame and mid-frame; means for opening the first hinge to pivot the midframe away from and towards a first lateral side of the attachment, and for closing the first hinge; means for moving the first hinge laterally back and forth across the rear frame; a front plate having attachment points for one or more material handling members; a second hinge between the mid-frame and the front plate; means for opening the second hinge to pivot the front plate away from the mid-frame and towards a second lateral side of the attachment, and for closing the second hinge; and means for moving the second hinge laterally back and forth across the mid-frame. The load handling member may thus be moved to work in a straight-ahead position or a position pointing to either side of a vehicle to which the attachment is fitted.

United States Patent [1 1 Marsden MATERIAL HANDLING EQUIPMENT [75]Inventor: Geoffrey Marsden, Ackworth,

Pontefract, Yorkshire, England [73] Assignee: R. E. Barker & Co.,Limited,

Featherstone, Yorkshire, England 22 Filed: Feb. 3, 1972 211 Appl. No.:223,224

[52] US. Cl. 214/730 [51] Int. Cl 1366f 9/14 [58] Field of Search214/730, 750, 731

[56] References Cited UNITED STATES PATENTS 2,945,610 7/1960 Wendt214/730 3,659,733 5/1972 Sinclair et al 214/730 Primary Examiner-GeraldM. Forlenza Assistant Examiner-Lawrence J. Oresky Attorney-Richard K.Stevens et al.

[ 1 June 12, 1973 57 ABSTRACT An attachment for a lifting vehicle,particularly a fork lift truck, comprising a rear frame having means forattachment to a vehicle; a mid-frame; a first hinge be tween the rearframe and mid-frame; means for opening the first hinge to pivot themid-frame away from and towards a first lateral side of the attachment,and for closing the first hinge; means for moving the first hingelaterally back and forth across the rear frame; a front plate havingattachment points for one or more material handling members; a secondhinge between the mid-frame and the front plate; means for opening thesecond hinge to pivot the front plate away from the mid-frame andtowards a second lateral side of the attachment, and for closing thesecond hinge; and means for moving the second hinge laterally back andforth across the mid-frame. The load handling member may thus be movedto work in a straight-ahead position or a position pointing to eitherside of a vehicle to which the attachment is fitted.

15 Claims, 9 Drawing Figures PATENIEB JUN] 2 ma SHEET 1 [IF 8 PAIENIEJUN 1 2191s sum 2 or a PAIENImJum zms SHEEN; 0F 8 PATENIEB JUN] 2 I973SHEET 5 0F 8 PATENIED JUN] 2 I973 3 738 5 1 2 SHEET 6 OF 8 MATERIALHANDLING EQUIPMENT This invention relates to material handlingequipment, and more particularly to an attachment for fork lift trucksand other lifting vehicles and to vehicles equipped with such anattachment.

The load carrier of a fork lift truck is generally directly mounted inthe carriage plate which is slidably mounted for vertical movement upand sown the mast. On such trucks there is no provision for pivoting theload carrier out of its straight-ahead position to project toward eitherside of the truck. Such a facility is useful for handling loads to eachside of a narrow aisle along which the truck can move only forwards andbackwards.

A number of attempts have been made to provide fork lift trucks orattachments therefor which will provide this facility. One proposal hasbeen to provide a rear frame for attachment to the truck, a mid-frameand a front frame bearing the load carrier, the midframe being pivotedat opposite ends thereof respectively to the rear and front frames. Thefront frame and thus the load carrier could thus be pivoted to eitherside of the truck. However, the load carrier would always follow anarcuate path, which is a disadvantage, as an aisle in which the truckworks would then have to be sufficiently wide to accommodate the widthof the truck and the full projection of the load carrier. In otherearlier arrangements a rear frame for attachment to the truck has had anelement mounted thereon for sliding movement transverse to the truck,the element bearing the load carrier. The load carrier has either beenfixed pointing to one side of the truck, or pivoted to move between astraight-ahead position and a position pointing to one side only of thetruck. Each such arrangement has limitations in that the load carriercan only work at one side of the truck.

In order to overcome this disadvantage a further proposal has been toprovide an attachment comprising a rear frame for attachment to thetruck, a mid-frame slidable on the rear frame transversely of the truckand a front frame mounted by releasable pivots at each side of themid-frame. By releasing the appropriate pivot and leaving the other onelocked the front frame could be pivoted about the locked pivot to therespective side of the truck, and could have a limited degree ofmovement sideways of the truck by sliding the mid-frame on the rearframe. The combined locking and pivot mechanism necessary for sucharrangements is cumbersome and complex, and the attachment isaccordingly heavy and limited in its operation, particularly as thesliding movement to either side is limited to somewhat less than halfthe width of the mid-frame.

According to the present invention an attachment for a lifting vehicle,particularly a fork lift truck, comprises a rear frame having means forattachment to a vehicle; a mid-frame; a first hinge between the rearframe and mid-frame; means for opening the first hinge to pivot themid-frame away from and towards a first lateral side of the attachment,and for closing the first hinge; means for moving the first hingelaterally back and forth across the rear frame; a front plate havingattachment points for one or more material handling mem bers; a secondhinge between the mid-frame and the front plate; means for opening thesecond hinge to pivot the front plate away from the mid-frame andtowards a second lateral side of the attachment, and for closing thesecond hinge; and means for moving the second hinge laterally back andforth across the midframe.

The invention also includes a vehicle having an attachment as aforesaidfitted thereto. The vehicle may preferably be a fork lift truck, inwhich case the attach ment means on the rear frame are means forsecuring that frame to the standard carriage plate of the fork lifttruck. The front plate may have attachment points for any contemplatedvariety of forks, arms and other material handling members.

In use, assuming that the attachment is fitted to the standard carriageplate of a fork lift truck and that the front plate is fittedwith forks,then, when the hinges are closed and in their normal position on the twoframes the frames and the front plate are folded flat one immediatelyahead of another and within the same lateral confines. The forks on thefront plate point directly forward and the truck operates as aconventional fork lift truck. The attachment does not impede this normaloperation, or does it impede the conventional side shifting of theforks, and the attachment as a whole, to right or left of thelongitudinal center line of the truck while maintaining the forks in aforward pointing direction.

Assume now that, looking forward from the driving position the firsthinge is at the left hand side of the rear frame, the second hinge is atthe right hand side of the mid-frame and it is desired to side stack tothe left of the truck. To do this the first hinge is opened to move themid-frame and front plate together about the hinge to take up a positionprojecting forwardly from, and at right angles to, the rear frame. Theforks then project to the left of the truck, and by traversing the firsthinge across the rear frame from its limit left hand to its limit righthand position the forks can be moved between positions projecting beyondthe lateral confines of the rear frame and lying substantially withinthose confines. If side stacking to the right is required, then thesecond hinge is opened to move the front plate relative to the mid-frameto take up a position extending forwardly from the mid-frame and atright angles to the mid and rear frames. The forks then project to theright of the truck and can be moved to lie substantially within thelateral confines of the plates by moving the second hinge to the leftacross the face of the midframe.

The arrangement according to the invention differs from the prior knownarrangements in that the hinges are themselves slidably movable on therespective frames and the range of movement of the attachment within thelateral confines of the truck is substantially increased over theprevious arrangements, without the need for complex and heavy lockingmechanisms. The saving in weight is, of course, of great importancesince it reduces the load on the mast of the fork lift truck and allowsan increased load weight to be carried. The invention thus provides amore versatile, lighter and simpler arrangement for converting a forklift truck to have a side-stacking capability.

Preferably the attachment is such that pivotal movement of the mid-frameaway from the rear frame occurs simultaneously with lateral movement ofthe first hinge across the rear frame, and that pivotal movement of thefront plate away from the mid-frame occurs simultaneously with lateralmovement of the second hinge across the mid-frame.

By carrying out these simultaneous movements it is possible to turn loadcarrying members secured to the front plate from a forward facing to aside facing position while maintaining the load carrying membersentirely within the confines of width of the attachment. Conversion toside-stacking can thus be effected in narrower aisles than was possiblein prior constructions Preferably, first and second locks are providedfor locking respectively the mid-frame to the rear frame at the secondlateral side, and for locking the front plate to the mid-frame at thefirst lateral side. Conveniently the locks may be linked to the hingeopening means so that the first lock is released before the first hingeis opened and the second lock is released before the second hinge isopened.

Desirably the hinge-opening means, hinge-moving means and locks are allhydraulically operated.

An embodiment of an attachment according to the invention will now bedescribed in more detail, by way of example only, with reference to theaccompanying drawings in which:

FIG.-l is an end elevation of the attachment with the front plate facingforward;

FIG. 2 is an isometric view of the attachment with the front platepivoted to one side;

FIG. 3 is an isometric view of the attachment with the front platepivoted to the other side;

FIG. 4 is a cross section through parts of the rear and mid-frames inthe direction of the arrow A;

FIG. 5 shows a detail of a hinge plate;

FIG. 6 is a cross-section through a hinge;

FIG. 7 is a cross section through a hinge detail;

FIG. 8 is a cross section through a locking device; and

FIG. 9 is a fluid circuit diagram.

Referring now to the drawings, and in particular to FIGS. 1 to 3, theattachment comprises a rear frame 1, a mid-frame 2 and a front plate 3.The rear face of the rear frame is provided with mounting members 4whereby the attachment may besecured to the conventional carriage plateof a fork lift truck. The front plate includes two bars 5 and 6 havingupper and lower edges 7 and 8 respectively of angle section to form astandard carriage plate on which a load handling member may be mounted,for example a pair of forks 9 as shown in broken lines in FIG. 1.

The mid-frame 2 is formed with webs 10 and 11 projecting above the upperand lower edges respectively of the frame. The upper edge of the frameand the upper web 10 form a clevis to which is secured a hinge pin 12passing through a self-lubricating bush (not shown) mounted in a boss 13carried at the endof a substantially triangular web 14 forming part of acarrier plate 15. The lower edge of the frame and the lower web 11form'a similar clevis cooperating with a boss 16 carried by a web 17forming part of the carrier plate 15. Again a hinge pin is secured tothe clevis coaxial with hinge 12, the hinge pin being rotatable in aself-lubricating bush within the boss 16. The mid-frame 2 is thus hingedto the carrier plate and can move between a closed position wherein themid-frame lies immediately in front of the rear frame (as shown inFIG. 1) and an open position with the mid-frame extending forwardlysubstantially at right angles to the rear frame, as shown in FIG. 2.

Pivotal movement between these positions is effected by twofluid-operated rams comprising cylinders 18 and 19 pivoted to thecarrier plate at 20 and 21 respectively, and pistons having piston rods22 and 23 pivoted at 24 and 25 respectively to the mid-frame.

The carrier plate 15 is mounted for movement back and forth across therear frame 1 in the following manner, shown most clearly in FIG. 4. Therear frame 1 is formed along its upper and lower edges with tracks 26and 27 respectively. Rotatably mounted at the upper part of the carrierplate 15 are rollers 28 and 29 running on the upper face '30 of thetrack 26. Roller 28 is formed with a flange 31 engaging the front face32 of the upper track 26, and is rotatably mounted by bearings 33 abouta pin 34 secured between plates 35 and 36 forming part of the carrierplate 15 and lying respectively to the front and rear of the track 26,the plates 35 and 36 being joined by a web 37. The rear plate 36 has atransverse extension 38 into which is screwed a further pin 39surrounding which is a further bearing 40 supporting a roller 41 forrotation. The roller 41 runs on the rear face 42 of the track 26. Theroller 29 is also flanged and is mounted for rotation in an identicalmanner to the roller 28. Roller 41 is mounted close to roller 28, and aroller similar to roller 41 is mounted close to roller 29.

The lower part of the carrier plate 15 is formed by a plate 43 welded tothe remainder of the carrier plate and rotatably supporting rollers 45and 46 running on the lower face 47 of the lower track 27. The rollers45 and 46 are mounted on the plate 43 in identical manner. Thus, roller45 is supported by bearings 48 mounted on a supporting bolt 49 passingthrough a hole 50 in the plate 43 and secured by a nut 51. A spacingboss 52 is welded to the plate 43, the bolt 49 passing through a bore 53in the boss, and a spacing washer 54 is positioned between the innerrace of the bearing 48 and the head 55 of the bolt to ensure that thehead 55 can not engage the roller 45. The roller 45 is formed with aflange 56 engaging the rear face 57 of the track 27.

At two spaced locations between the rollers 45 and 46 further rollerssuch as 58 are rotatably mounted on the carrier plate 15 to run on thefront face 59 of the lower track 27. To accommodate each such roller 58the plate 43 is cut away to receive a socket 60 bolted by a bolt 61 tothe remainder of the carrier plate 15 and having a tapped bore 62.Received in this bore is the end of a bolt 63 on which is axiallysecured a bearing 64 supporting the roller 58 for rotation. The roller58 and the head of the bolt 63 are also accommodated in the cut-awaysection of the plate.

It will thus be seen that the carrier plate 15 is mounted for freemovement across the rear frame. The rollers 41 and 58 engaging behindand in front of the upper and lower tracks respectively prevent themidframe from pulling away from the rear frame when a load is beingcarried and ensure smooth movement of the carrier plate 15 and mid-frameacross the rear frame even under load. The flanges 31 and 56 on rollers28, 29 and 45, 46 respectively prevent the carrier plate 15 from pullingoff the tracks 26 and 27 by a forward movement of the lower partthereof, such as could be caused by accidental contact of the attachmentwith the ground.

The carrier plate 15 is moved laterally across the rear frame 1 by twosingle-acting fluid-operated rams. The first of these rams comprises acylinder 65 mounted on the rear frame and a piston having a piston rod66. The

second such ram comprises a cylinder 67 mounted on the rear frame belowthe level of the cylinder 65, and a piston having a piston rod 68. Thetwo cylinders are fixed at opposite lateral sides of the rear frame andthe piston rods extend in opposite directions across the frame. Thepiston rods 66 and 68 each carry a pulley 69 and 70 respectively attheir free ends. A chain 71 is anchored at one end 72 above the cylinder65, passes round the pulley 69, round the pulley 70 and is anchored atits other end 73 below the cylinder 67. On its run 74 between the twopulleys the chain is anchored to the carrier plate as shown in FIG. 5.Referring to this Figure the plate 15 has a mounting element 75 securedto the rear surface thereof by four set screws such as 76. The twosections of the run 74 of the chain are respectively anchored to ananchor plate 77 of the mounting element 75 by pins 78 passing throughbores 79 in the anchor plate and also passing through links of thechain. The chain may be continuous or may be discontinuous, the twoparts thus being joined by the anchor plate.

The front plate 3 is mounted for pivotal movement and lateral movementrelative to the mid-frame 2 in a manner similar in many respects to thatalready described for the mounting of the mid-frame relative to the rearframe. Thus the front plate is provided with upper and lower axiallyaligned hinge bosses 80 and 81, each surrounding a self-lubricating bushwhich in turn surrounds a hinge pin secured across the clevis formedrespectively between the upper edge of a carrier plate 82 and an upperweb 83 projecting therefrom, and between the lower edge of the carrierplate 82 and lower web 84 projecting therefrom. Pivotal movement of thefront plate 3 on the carrier plate 82 is effected by two fluid operatedrams comprising cylinders 85, 86 having pistons and piston rods 87, 88respectively, the cylinders being pivotally mounted at 89 and 90 to thecarrier plate 82 and the piston rods being pivotally mounted at 91 and92 to the front plate 3.

The carrier plate 82 is mounted for sliding movement across themid-frame by upper and lower cooperating slides and slideways, the twoassemblies being inverted one with respect to the other but otherwisebeing identical. The upper slide assembly comprises a squaresectionmember 93 secured along the upper edge of the mid-frame 2, the member 93being formed with a longitudinally extending cylindrical bore 94 and alongitudinally extending slot 95 directed radially from the bore 94 atthe lower extremity thereof. Secured to the carrier plate 82 is a slidecarrier 96 carrying either a single cylindrical member extending thelength of the slide carrier 96, or two or more shorter, spacedcylindrical members 97. In each case the cylindrical member or membershas a surface of self-lubricating material and is a close fit in theslideway formed by the bore 94, the slide carrier 90 extending throughthe slot 95. Visible parts of the lower slide and slideway, identical toparts of the upper assembly, are shown on the drawings by the samereference numerals as for the parts of the upper assembly, with thesuffix a. The disposition of the slides and slideways are such that thecarrier plate is held out of all contact with the mid-frame, except forthe slide and slideway contact.

Sliding movement of the carrier plate 82 and thus the front plate 2across the mid-frame is effected by two single-acting rams havingcylinders 98, 99 and piston rods 100, 101 carrying pulleys 102, 103around which passes a chain 104 anchored to the mid-frame at its ends105, 106 above cylinder 98 and below cylinder 99 respectively, andanchored to the carrier plate in the same fashion as chain 71 isanchored to carrier plate 15 (FIG. 5).

It will now be evident that in order to operate all the fluid-operatedrams, fluid must be fed through from the rear frame to the mid-frame,and to both ends of the rams for pivoting the mid-frame and front plate.To allow this fluid feed, the hinges 20,21, 89 and for the cylinders 18,19, 85 and 86 are all constructed as shown in FIG. 6, and hinges 107,108 coaxial with the main hinges between the carrier plate 15 and themidframe 2 are of similar construction.

FIG. 6 shows, as an example of one of these hinges, the hinge 20 in theposition with the cylinder 18 lying against the rear frame 1, Le. withthe hinge closed. The carrier plate 15 is formed with two opposed clevissections 109, 110 between which there fits a stem 111 formed on the endof the cylinder 18. The stem and the clevis are drilled to receive ahinge pin 112 formed to have lands and grooves and also formed to haveaxial passages for fluid transmission. The clevis sections 109, 110 areeach drilled to form a fluid passage 113, 114, the passages being tappedat 115, 116 to receive hose connections, and being closed by plugs 115a,116a at their other ends. The cylinder stem 111 is formed with two fluidpassages 117, 118, one opening directly into the fixed end of thecylinder, and the other opening out of the stern into a conduit 121. Thepassages 117, 118 are drilled through from the exposed edge of the stemand these ends are then plugged by plugs such as 120. The conduit 121 issecured externally of the cylinder and leads to the rod end of thecylinder where it is connected to a port in the cylinder wall openinginto the rod end of the cylinder.

The passage 113 in clevis section 109 is aligned with and opens into agroove 123 in the hinge pin, and this groove communicates by an axialpassage 124 with a further groove 125 aligned with the fluid passage117. A passage for fluid through the hinge pin from clevis section 109to cylinder 18 whatever the relative position of the parts. Similarly,groove 126, axial passage 127 and groove 128 from a passage for fluidfrom clevis section 109 to cylinder 18. Other grooves formed round thehinge pin house O-ring seals 129 for preventing fluid leakage along theoutside of the pin. The pin is also formed with grooves 130, 131receiving circlips 132, 133 for properly locating the pin and holding itin position relative to the clevis sections 109 and 110. The axialpassages 124 and 127 are drilled in form opposite ends of the hinge pinand the open ends closed by plugs 134 and 135.

Hinges 21, 89 and 90 are identical to that described above. Hinges 107and 108 differ therefrom only in detail of the hinge ends and circlipgrooves, the other grooves and axial passageways being identical tothose described. However, as there is no cylinder such as 20 associatedwith such hinges an end block 136 as shown in FIG. 7 is mounted betweenthe clevis portions of the hinge, which form part of the mid-frame, andis secured to the carrier plate 15. The end block 136 has fluid passages137, 138 aligned with the grooves 125, 128 of the hinge pin and openinginto tapped holes 139, 140 into which hose connection nozzles may bescrewed.

The remainder of the fluid connections will now be described in relationto FIG. 2, 3 and 8. The movements of the attachment are controlled fromthe drivers position of the fork lift truck by a single lever 141controlling a three-position valve 142, and a push-button 143 mounted onthe end of the lever and operative to complete an electrical circuit tothe solenoid of a twoposition solenoid valve 144. The lever 141 ismovable from a central position to the left or right of the truck, tocontrol lateral shifting of the frames to the appropriate side of thetruck. Power is taken from the standard hydraulic system of the forklift truck through power and drain conduits 145 and 146, branches 147and 148 of which lead to valve 144. Two conduits from valve 142 and twofrom valve 144 are connected by flexible hoses to a mounting block 149on the rear frame 1 of the attachment, and four corresponding conduitsfrom the valves are connected by flexible hoses to a second mountingblock 150 on the rear frame. Each mounting block comprises two sequencevalves 151 to 154 each having a non-return valve 155 to 158 in paralleltherewith, and appropriate connectors.

From the mounting block 149 rigid conduits 159 and 160 (for examplesteel tubes) extend respectively to cylinders 65 and 67. The mountingblock is connected to the opposite ends of the cylinders 18 and 19 byconduits 161 and 162, which comprise sections of rigid conduit 161a,162a leading from the block 149 to a connection box 163, and section offlexible hose 161b, 162b leading from the connection box 163 to theclevis sections 109, 110 of binge 20, these clevis sections beinginterconnected with those of the clevis sections of hinge 21 by rigidconduits 164, 165.

From the mounting block 150 conduits 166 to 169 are connectedrespectively to cylinders 98, 99 and to opposite ends of cylinders 85and 86. Conduits 166 to 169 each comprise rigid conduit sections 1660 to1690 leading to a connection block 170; flexible hose sections l66b to16912 extending from the block 170,

through a hole 171 in the carrier plate 15 to a connection block 172;and rigid conduit sections 1660 to 169C extending from the block 172 tothe end blocks 136 of the hinges 107 and 108. Conduits 166 and 167 arethen continued by rigid conduit sections 166d, 167d to cylinders 98 and99. Conduits 168 and 169 are continued from the clevis sections of hinge108 by rigid conduit sections 168d, 169d to a connection box 173, andthence by flexible hose sections 168e, !169e to the clevis sections ofhinge 90, these clevis sections being interconnected with those of hinge89 by rigid conduits 174 and 175.

Referring now to FIGS. 2 and 3 locking devices 176 and 177 are mountedon the rear frame and mid-frame respectively, the device 176 being forlocking the rear frame and mid-frame together, and the device 177 beingfor locking the mid-frame and front plate together in their closedpositions. Each lock is fluidoperated, lock 176 being controlled byfluid pressure in conduit 162, and lock 177 by fluid pressure in conduit169. Each lock is of identical construction, as shown in H0. 8.

Referring to this Figure, each lock comprises a substantiallyrectangular housing 178 having mounting flanges 179 by way of which itmay be bolted to the respective frame. Slidably mounted in a chamber 180in the housing is a plunger 181 having a latching end 182 normallyprojecting through a slot 183 in one end of the housing. The other endof the housing is closed by a cover plate 184 secured by bolts 185, thecover plate having a slot 186 through which a stern 187 of the plungerprojects. A compression spring 188 surrounds that part of the stem 187that lies within the housing and biases the plunger so that the latchingend 182 projects. Formed in the housing are two cylinders 189 and 190,each having a piston 191, 192 slidable therein. Tapped bores 193, 194open into the cylinders and fluid conduit connectors (not shown) arescrewed into the open ends of the tapped bores and connected to theappropriate fluid supply conduit. It will be evident that when fluidunder pressure is admitted into the cylinders 189, 190, the plunger willbe moved against the spring 188 to withdraw the latching end 182 intothe housing. The latching end 182 of the lock 176 is engageable with acatch rail 195 on mid-frame 2. The latching end of the lock 177 isengageable with the bar 6 of the front plate. Thus, when the rams 18 and19 are retracted so that the mid-frame lies against the rear frame thetwo frames are held together by the lock 176. In this position the twoframes are substantially contiguous, but the arrangement is such thatthe pivot axes at 24 and 25 between the piston rods 22 and 23 and themidframe lie slightly in front of the pivot axes at 20 and 21 betweenthe cylinders 18 and 19 and the carrier plate 15. This ensures thatpivotal movement of the midframe will commence immediately on extensionof the rams. Similarly when the rams between the front plate andmid-frame are retracted the front plate lies immediately ahead of andsubstantially contiguous with the mid-frame and is held in that positionby the lock 177. The pivotal axes at 91 and 92 between the piston rods87, 88 and the front plate lie slightly in front of the pivot axes 89and between the cylinders 85, 86 and the mid-frame, so that pivotalmovement of the front plate commences when extension of the rams isstarted.

Operation of the attachment will now be described. This operation iseffected by means of two controls only, the lever 141 which controlslateral shifting and the push-button 143 which controls pivotalmovement. Assuming for the moment that pivotal movement is not required,and that the only action necessary is a lateral shifting of the loadcarrying members projecting in a straight ahead position, then the onlycontrol necessary is lever 141, and push-button 143 is not operated.Lateral shifting to the right hand side of the vehicle, facing forwardly(indicated by the arrow 2 in FIG. 9), is effected by moving controllever 14] to the right so that fluid flow through the valve 142 iseffected by the connections in the section 142a of this valve. Fluidpressure is accordingly admitted to conduit 167 and, through sequencevalve 152, to conduit 160, the pressure in the former conduit having noeffect on the piston in cylinder 99. However, the fluid in conduit movesthe piston in cylinder 67 towards the right hand side of the attachment,so causing the carrier plate 15 to traverse across the rear frame 1,carrying with it the mid-frame 2. During this movement, fluid exhaustsfrom cylinder 65 through line 159 and the section 142a of the valve 142.For return movement to the left the lever 141 is moved to the left tomake the fluid connections in section 14212 of the valve. This appliesfluid under pressure to conduit 159 and, via the delay valve 153, toconduit 166. The delay valve 153 will only open when full systempressure is applied to it, which will not happen until the piston incylinder 65 has been driven back to its full left hand position by thefluid in conduit 159, fluid from cylinder 67 being exhausted throughconduit 160, non-return valve 150 and part 142b of valve 142. Thismovement returns the carrier plate 15 to its position at the left handextremity of the rear frame 1, and at this stage the rear frame,mid-frame and front plate are again lying one in front of the otherwithin the same lateral confines. If the lever 141 is moved back to itscentral position at this time then no further movement occurs. However,if the lever is maintained in the left hand position then full systempressure builds up at the sequence valve 153 and pressure fluid passesto cylinder 98 through conduit 166. This has the effect of driving thepiston in cylinder 98 to the left so shifting the carrier plate 82 andfront plate along to the left hand end of the mid-frame, in thedirection of the arrow L in FIG. 9. During this movement fluid exhaustsfrom cylinder 99 through conduit 167 and the section 142b of valve 142.Movement of the lever 141 to the right will commence movement of thefront plate back to its central position, where it can be stopped bycentralizing the lever 141 at the appropriate time. During such movementsequence valve 152 prevents flow of fluid to cylinder 67. The attachmentthus givesthe fork lift truck a conventional side shift facility toeither side of the truck.

Assume now that it is desired to work with the load handling membersprojecting to the left hand side of the truck. With the mid-frame andfront plate in their central positions this is achieved by moving thecontrol lever 141 to the right and at the same time pressing thepush-button 143. When this is done fluid under pressure is suppliedthrough section 142a of valve 142 to conduits 160 and 167 as alreadydescribed, and, via conduit 147 to the valve 144, which has been openedby operation of the push-button 143, and from the valve 144 to conduit168 and, via sequence valve 151 to conduit 162. As before, fluidpressure in conduit 167 has no effect, and also fluid pressure inconduit 168 will have no effect since the pistons in cylinders 85 and 86are already fully retracted. However, fluid pressure in conduit 162first releases the lock 176 and then moves the pistons in cylinders 18and 19 to extend these rams, while at the same time the fluid pressurein conduit 160 extends the ram formed by cylinder 67 and piston rod 68.Thus, the mid-frame pivots on the carrier plate 15 into its left-facingposition, fluid being exhausted from cylinders 18 and 19 through conduit161, valve 144, conduit 148 and valve section 142a, while at the sametime the carrier plate 15 traverses to the right across the rearframe 1. The simultaneity of these two actions means that the loadcarrying member can be brought into its left-facing position without atany time projecting beyond the lateral confines of the rear frame 1.When the full pivotal movement is completed the pushbutton 143 isreleased so closing valve 144, whereupon the fluid under pressure locksthe rams having cylinders 18 and 19 in their extended position. Movementof the control lever 141 to the left without operation of thepush-button 143 will then cause fluid under pressure to pass to cylinder65 to drive the carrier plate 15 back to the left hand side of the rearframe so that the load carrying elements are moved to a position to theleft hand side of the fork lift truck. Thus, traversing of the loadcarrying members in their left-facing position can be effected bymovement of the control lever 141.

To return the attachment to its normal position the mid-frame is firsttraversed to its right hand position on the rear frame (if not alreadythere) by making connections 142a through valve 142. Then the controllever is moved to its left hand position to make connections 142b andthe push-button 143 is operated at the same time. Thus, fluid underpressure is applied to conduit 159, and, through delay valve 153 toconduit 166, and fluid under pressure is also applied through conduit148 to valve 144. From this open valve, pressure fluid is applied toconduit 161 and, through the delay valve 154 to conduit 169. As alreadyexplained this condition, due to the delay valve 153, has no effect onthe piston in cylinder 98, but commences a shift to the left of thepiston in cylinder 65, so commencing a left traverse of the carrierplate on the rear frame. Similarly, the delay valve 154 effectivelyprevents operation of the rams comprising cylinders 85 and 86, the fluidpressure in conduit 161 causing retraction of the rams having cylinders18 and 19, and thus pivoting the midframe back to its position againstthe rear frame. Once again the pivotal and traversing movements takeplace simultaneously so that the load carrying members turn within thelateral confines of the rear plate. During this movement fluid exhaustsfrom cylinders 18 and 19 through conduit 162 and the non-return valve155, open valve 144 and part 142 b of the valve 142. Simultaneouslyfluid exhausts from cylinder 67 through conduit 160, the non-returnvalve 156 and connections 14212 of the valve 142.

It will be understood that when the load carrying members are requiredto project to the right hand side of the truck movement of the controllever 141 to the left to bring section 142b into operation andsimultaneous operation of the push-button 143 will cause extension oframs having cylinders 85, 86 and 98 in a manner analagous to thatdescribed above. The pivotal movement of the load carrying members isthus again effected within the natural confines of the rear frame. Whenfully pivoted, the push-button 143 is released and traversing movementof the front plate on the midframe can then be effected by appropriatemovement of the lever 141. To fold the front plate back into its closedposition the control lever 14] is moved to the right and the push-button143 operated whereupon the rams having cylinders and 86 are retractedand the ram having cylinder 99 is extended, again in a manner analogousto that already described.

It will now be evident that the invention provides an attachment whichmay be used to give a fork lift truck conventional side shiftingfacility and alsofacility for stacking to the left and right of the forklift truck. These objectives are achieved by an attachment of simpleconstruction, and the desired effects can be achieved by a singlecontrol lever and control button so making operation of the attachmentvery easy.

What 1 claim is:

1. An attachment for a lifting vehicle, particularly a fork lift truck,comprising a rear frame having means for attachment to a vehicle; amid-frame; a first hinge between the rear frame and the mid-frame; meansfor opening the first hinge to pivot the mid-frame away from and towardsa first lateral side of the attachment, and for closing the first hinge;means for moving the first hinge laterally back and forth across therear frame; a front plate having attachment points for one or morematerial handling members; a second hinge between the mid-frame and thefront plate; means for opening the second hinge to pivot the front plateaway from the mid-frame and towards a second lateral side of theattachment, and for closing the second hinge; and means for bodilyshifting the second hinge laterally back and forth across and along thelongitudinal axis of the mid-frame.

2. An attachment according to claim 1 in which the means for attachmentto a vehicle comprise means for securing the rear frame to the carriageplate of a fork lift truck.

3. An attachment according to claim 1 and including first and secondlocks for locking respectively the midframe to the rear frame at thesecond lateral side, and for locking the front plate to the mid-frame atthe first lateral side.

4. An attachment according to claim 3 in which the locks are linked tothe hinge opening means so that the first lock is released before thefirst hinge is opened and the second lock is released before the secondhinge is opened.

- 5. An attachment according to claim 4 in which each hinge is mountedon a carrier plate movable laterally tively and hydraulically operatedmeans for moving the catch against the biasing force to move said catchout of locking engagement.

7. An attachment according to claim 5 in which each ram comprises acylinder pivoted to the carrier plate and a piston with a piston rodpivoted to the mid-frame or front plate respectively, and each cylinderis pivoted by a stern fitting between two sections of a clevis and ahinge pin passing through the stern and the clevis sections, the hingepin being formed with passages for feeding hydraulic fluid from boresformed in the clevis sections to bores formed in the cylinder stem andvice versa.

8. An attachment according to claim 5 in which the carrier plate of thefirst hinge is mounted for lateral movement over the rear frame byrollers journalled at the upper and lower parts of the carrier plate andrunning respectively on upper and lower faces of upper and lower trackson the rear frame.

9. An attachment according to claim 8 in which the upper rollers haveflanges engaging the upper track on the front face thereof and the lowerrollers have flanges engaging the lower track on the rear face thereof.

10. An attachment according to claim 8 in which the upper and lowerparts of the carrier plate have further rollers journalled thereon withaxes of rotation at right angle to said rollers, the upper furtherrollers engaging the rear face of the upper track and the lower furtherrollers engaging the front face of the lower track.

11. An attachment according to claim 5 in which the carrier plate of thesecond hinge has slides engaging slideways on the front face of themid-frame to allow the carrier plateto slide laterally on the mid-frame,the slide and slideways interlocking to hold the carrier plate out ofany further contact with the mid-frame.

12. An attachment according to claim 5 in which the means for moving thehinges laterally back and forth across the respective ones of the rearframe and midframe each comprise fixed pairs of hydraulic rams, eachpair comprising a first hydraulic ram having a cylinder fixed at onelateral side of the plate and extending substantially half-way acrossthe frame, a second hydraulic ram having a cylinder fixed at the otherlateral side of the frame below the level of the cylinder of the firsthydraulic ram and extending substantially halfway across the frame, eachram having a piston and a piston rod extendable in opposite directionacross the frame, the piston rods each carrying a pulley at their freeend, and a chain anchored at its ends adjacent to the ends of thecylinders nearer the center of the frame and extending around thepulleys and secured in its run between the pulleys to the carrier plate.

13. An attachment according to claim 12, in which is such that pivotalmovement of the mid-frame away from the rear frame occurs simultaneouslywith lateral movement of the first hinge across the rear frame, and thatpivotal movement of the front plate away from the mid-frame occurssimultaneously with lateral movement of the second hinge across themid-frame.

14. An attachment according to claim 13 wherein said simultaneouspivotal movement of the mid-frame and lateral movement of the firsthinge is effected by simultaneous extension of the respective pivotallymounted hydraulic ram, and an appropriate one of the respective fixedpair of hydraulic rams, and said simultaneous pivotal movement of thefront plate and lateral movement of the second hinge is effected bysimultaneous extension of the other respective pivotally mountedhydraulic ram and an appropriate one of the other respective fixed pairof hydraulic rams.

15. An attachment according to claim 14 and including sequence valvesfor delaying application of fluid under pressure until the pressure isthe full system pressure, said sequence valves controlling fluid flow toextend the pivotally mounted rams and controlling fluid flow to thoseones of the respective pairs of fixed rams which extend to give lateralmovement of the midframe and front plate respectively from their normalpositions directly ahead of the rear frame.

1. An attachment for a lifting vehicle, particularly a fork lift truck,comprising a rear frame having means for attachment to a vehicle; amid-frame; a first hinge between the rear frame and the mid-frame; meansfor opening the first hinge to pivot the mid-frame away from and towardsa first lateral side of the attachment, and for closing the first hinge;means for moving the first hinge laterally back and forth across therear frame; a front plate having attachment points for one or morematerial handling members; a second hinge between the mid-frame and thefront plate; means for opening the second hinge to pivot the front plateaway from the mid-frame and towards a second lateral side of theattachment, and for closing the second hinge; and means for bodilyshifting the second hinge laterally back and forth across and along thelongitudinal axis of the mid-frame.
 2. An attachment according to claim1 in which the means for attachment to a vehicle comprise means forsecuring the rear frame to the carriage plate of a fork lift truck. 3.An attachment according to claim 1 and including first and second locksfor locking respectively the mid-frame to the rear frame at the secondlateral side, and for locking the front plate to the mid-frame at thefirst lateral side.
 4. An attachment according to claim 3 in which thelocks are linked to the hinge opening means so that the first lock isreleased before the first hinge is opened and the second lock isreleased before the second hinge is opened.
 5. An attachment accordingto claim 4 in which each hinge is mounted on a carrier plate movablelaterally across the respective frame, each hinge opening meanscomprises a pivotally mounted hydraulic ram operating between therespective carrier plate and the mid-frame or front plate respectively,and the locks are hydraulically operated.
 6. An attachment according toclaim 5 in which each lock comprises a catch member biased into lockingengagement with the mid-frame or front plate respectively andhydraulically operated means for moving the catch against the biasingforce to move said catch out of locking engagement.
 7. An attachmentaccording to claim 5 in which each ram comprises a cylinder pivoted tothe carrier plate and a piston with a piston rod pivoted to themid-frame or front plate respectively, and each cylinder is pivoted by astem fitting between two sections of a clevis and a hinge pin passingthrough the stem and the clevis sections, the hinge pin being formedwith passages for feeding hydraulic fluid from bores formed in theclevis sections to bores formed in the cylinder stem and vice versa. 8.An attachment according to claim 5 in which the carrier plate of thefirst hinge is mounted for lateral movement over the rear frame byrollers journalled at the upper and lower parts of the carrier plate andrunning respectively on upper and lower faces of upper and lower trackson the rear frame.
 9. An attachment according to claim 8 in which theupper rollers have flanges engaging the upper track on the front facethereof and the lower rollers have flanges engaging the lower track onthe rear face thereof.
 10. An attachment according to claim 8 in whichthe upper and lower parts of the carrier plate have further rollersjournalled thereon with axes of rotation at right angle to said rollers,the upper further rollers engaging the rear face of the upper track andthe lower further rollers engaging the front face of the lower track.11. An attachment according to claim 5 in which the carrier plate of thesecond hinge has slides engaging slideways on the front face of themid-frame to allow the carrier plate to slide laterally on themid-frame, the slide and slideways interlocking to hold the carrierplate out of any further contact with the mid-frame.
 12. An attachmentaccording to claim 5 in which the means for moving the hinges laterallyback and forth across the respective ones of the rEar frame andmid-frame each comprise fixed pairs of hydraulic rams, each paircomprising a first hydraulic ram having a cylinder fixed at one lateralside of the plate and extending substantially half-way across the frame,a second hydraulic ram having a cylinder fixed at the other lateral sideof the frame below the level of the cylinder of the first hydraulic ramand extending substantially halfway across the frame, each ram having apiston and a piston rod extendable in opposite direction across theframe, the piston rods each carrying a pulley at their free end, and achain anchored at its ends adjacent to the ends of the cylinders nearerthe center of the frame and extending around the pulleys and secured inits run between the pulleys to the carrier plate.
 13. An attachmentaccording to claim 12, in which is such that pivotal movement of themid-frame away from the rear frame occurs simultaneously with lateralmovement of the first hinge across the rear frame, and that pivotalmovement of the front plate away from the mid-frame occurssimultaneously with lateral movement of the second hinge across themid-frame.
 14. An attachment according to claim 13 wherein saidsimultaneous pivotal movement of the mid-frame and lateral movement ofthe first hinge is effected by simultaneous extension of the respectivepivotally mounted hydraulic ram, and an appropriate one of therespective fixed pair of hydraulic rams, and said simultaneous pivotalmovement of the front plate and lateral movement of the second hinge iseffected by simultaneous extension of the other respective pivotallymounted hydraulic ram and an appropriate one of the other respectivefixed pair of hydraulic rams.
 15. An attachment according to claim 14and including sequence valves for delaying application of fluid underpressure until the pressure is the full system pressure, said sequencevalves controlling fluid flow to extend the pivotally mounted rams andcontrolling fluid flow to those ones of the respective pairs of fixedrams which extend to give lateral movement of the mid-frame and frontplate respectively from their normal positions directly ahead of therear frame.